Over the years, hospital beds have evolved into useful aids for facilitating the performance of various medical procedures. One particular type of hospital bed that has become a useful medical aid is the maternity bed upon which a woman rests while giving birth. A maternity bed includes many of the elements of a conventional hospital bed. The bed has a base that serves as the ground support unit. A litter, located above the base, serves as the support frame for a mattress upon which the woman rests. A maternity bed is further constructed so that the portion of the litter that supports the woman's upper body, referred to as the Fowler weldment, is able to pivot relative to the adjacent section, the seat weldment. A maternity bed is further constructed so that the section of the litter located rearward of the seat weldment, the leg-foot frame, is either removable or retractable. The ability to move the leg-foot frame away from the seat weldment frees the space adjacent the seat weldment so that medical personnel can have easy access to the open end of the birth canal in order to both assist in the delivery of the infant and to perform any necessary post-delivery medical procedures on the mother.
A maternity bed is also often provided with a mattress having one or more sections of adjustable firmness. This is because during the delivery and post-delivery processes, it is desirable to have the mother resting on surfaces having different degrees of hardness. For example, during the initial stages of the delivery process and after delivery, it may be desirable to have the mother resting on a relatively soft mattress. During the actual delivery process, however, it may be preferably to have the mother resting on a harder surface that she can push against in order to facilitate the actual delivery. More specifically, it is desirable to have the mother's perineum, which defines the birth canal, pressing against a firm surface. Also, after delivery, it is desirable to have the mother's perineum seated on a firm surface after delivery in the event there is a need to perform any post-delivery medical procedures on the woman's perineum.
In the past, in order provide a mattress with adjustable firmness for the woman's perineum it has been the practice to simply place an inflatable bladder in the portion of the mattress on which the woman's buttocks rest. This section of the mattress is referred to as the seat section. More specifically, the bladder is sandwiched between two foam cushions that provide the mattress with its form. When there is a need to increase mattress firmness, the bladder is inflated. The inflation of the bladder compresses the cushions to increase the firmness of the seat section of the mattress.
A disadvantage of this current mattress construction is that, while the bladder increases the firmness of the seat section, the increase is mainly in the center of the section. While this increased firmness is useful, it would be more desirable if it was present at the perineal end of the mattress, the end against which the mother's perineum is seated. Moreover, this bladder is loosely fitted in the mattress. It can inadvertently be placed, or shifted, to a position even more distal to the perineal end of the mattress. If this occurs, the increased firmness provided by the bladder may not be a location where it offers any help during the delivery or post delivery processes. If this shifting occurs, medical personnel may not be aware of it until the woman is already resting on the bed. If this is the situation it may be difficult, if not impossible, to reset the bladder so that the expectant mother is able to take advantage of its usefulness.